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Design-In of Reliability Through Axiomatic Design Introduction AGJSR 31 )Special Issue) 2013: 314-324 Dezhen Yang et al Design-in of Reliability through Axiomatic Design Dezhen Yang; Yi Ren; Zili Wang and Linlin Liu School of Reliability and Systems Engineering, Beihang University, Beijing, China ABSTRACT Sp. Issue 2013/ # Paper 2 To completely meet the requirements of reliability design in the Corresponding author: product designing, an axiom-based Design-in Reliability approach Yi Ren is proposed. In light of the axiomatic design principles, products are Mailing address: No. 37, Xueyuan Road, Haidian District, Beijing, designed preliminarily to establish their functional requirements. 100191, P. R. China According to these, functions preserving requirements are augmented, E-mail: [email protected] which constitute a Functional Requirement Preserving domain included Tel: +86-10-82313173 in functional domain, and derives the parameterized solution for Fax: +86-10-82317663 reliability design systematically. Subsequently, the design parameters are augmented and optimized to achieve the functions preserving requirements. Mapping model of the augmented functional domain and the physical domain is established. And a solutions evaluation approach KEYWORDS based on Independence Axiom is proposed. Ultimately, via identifying the potential failure modes from the perspective of the disappearance Keywords-Reliability; or reduction of functions preserving capability, a control process is Independence axiom; Axiomatic design; Failure modes mitigation; elaborated to mitigate the failure modes on the basis of independence Functional requirement preserving axiom and logic decision in order for the reliability requirements to be domain; Temperature sensor implemented. Being exemplified by the design of a temperature sensor, the present study demonstrates that all approaches are feasible, efficient, and could be applied in real engineering scenarios. Introduction (Diyar, et al., 2011). Currently, reliability test is the main method for evaluation, but it could be carried As an optimum approach for product design, out until the prototypes are manufactured, which reliability design is to minimize the products’ is time-consuming and is prone to redesigning flaws (Huang and Zhang, 2009; Wanget al., 2010; (Yao, et al., 2012). Although a new approach Xiao et al., 2012). Its core idea is to progressively through simulation has been proposed recently, it understand the loads and stresses of each component, is not applicable to system-level products for its gradually recognize the failure modes and complexity. All the deficiencies in those methods mechanism, actively eliminate the exposed failure restrain the application and development of modes or reduce the occurrence probabilities, and reliability technology in engineering practices narrow the uncertainties and satisfy the reliability (Gong , et al., 2012; Li, et al., 2011). requirements (GEIA-STD-0009, 2009). The Orienting to product development processes, traditional technology of reliability design, being professor Nam Pyo Suh developed Axiomatic more dependent on “experience”, often make it Design (AD) principles (Pyo, 1990), which laid difficult for the results to be evaluated directly a scientific foundation for designers, especially in as they are relatively implicit (Michael , 2009; the design processes of large system design (Suh, Yan, et al., 2011; Zhao, et al., 2012). Thus, it is 1995; Suh, 2001), software design (Suh, et al., difficult or even impossible to compensate for or 2000; Suh, 2001), manufacturing system design evade the shortcomings of a poor design concept (Suh, 2001; Kulak, et al., 2005), human–machine developed in the early stages of the design process 314 AGJSR 31 )Special Issue) 2013: 314-324 Dezhen Yang et al systems (Helander, 2007), materials and materials- expressed as processing (Nakao, et al., 2007; Kulak, et al., 2010), product design (Kulak, et al., 2010; Tang, et al., 2007), decision making (Kulak , et al., 2010; Celik, (1) et al., 2009), safety-critical system (Ahmed , et al., 2007), and supply chain management (Kulak , et where is the second level al., 2010; Schnetzler, et al., 2007). These principles functional requirement vector; [A]n×d is the design are widely used to solve various design problems matrix that characterizes the design. Each entry aij and provide better design solutions in the shortest of [A]n×d relates the ith FR to the jth DP, denoted term as they offer a systematic research process in by aij=∂FRi/∂DPj. n does not have to be equal to a design space which becomes complicated with d, namely during the decomposition process, the customer needs. Also, the fact that they can be design matrix developed may not be square; and generalized to different design areas renders them is the second level design even more effective and powerful. parameter vector. However, how to apply the principles to achieve the object of “Design-in of reliability” still (2) Design Axioms needs further studies. The present research thus There are two design laws in the form of axioms: the proposes an approach in which engineers could Independence Axiom and the Information Axiom. determine explicit reliability requirements of the (A) The Independence Axiom states that the products simultaneously with the applications independence of functional requirements of AD principles for product design, analyze (FRs) must always be maintained, where FRs failures that cause difficulties for the realization are defined as the minimum set of independent of reliability thoroughly, and take measures to requirements that characterize the design mitigate them. goals (Kulak and Kahraman, 2010). In order to satisfy the Independence Axiom, [A]n×d Product Design through Axiomatic Design matrix should have an uncoupled or decoupled Principles design, namely the [A]n×d matrix should be square and must be diagonal or triangular. (1) Design Decomposition (B) The Information Axiom states that, among the A design description usually consists of multiple design solutions that satisfy the independence abstraction levels with the higher levels being more axiom, the best solution is the one that has abstract and the lower levels more detailed. At the lowest information content. The paper each level, there is a set of functional requirements conforms to the Independence Axiom only. (FRs). To decompose this set of FRs, the designer (3) A Case Study of Temperature Sensor needs to identify the set of design parameters (DPs) The main functional requirements of a temperature at this level. Such decomposition process, which sensor (TS) are to monitor the temperature of its alternates between design domains, is referred to installation environment in real-time (Anderson, as the ’zigzagging process’ (see figure 1). In this 2012). The aim is to prevent accidents caused by process, the lower-level FRs are consistent with over rising temperatures. Therefore, two lower- the DPs chosen and its parent FR (Suh, 2001). level functional requirements could be determined: The mapping between all the upper-level FRs and sensing the temperature (-55~125) of its installation DPs has to be realized before these FRs and DPs environment in real-time and outputting the can be decomposed to the lower-level FRs and temperature information (stimulating and DPs. This progressive process could be optimized transmitting the electrical signals of temperature). hierarchically. Each one should be mapped to one design In figure 1, the mapping between all the parameter at least. We choose a thermistor which same-level FRs and DPs can be mathematically could sense the environmental temperature using 315 AGJSR 31 )Special Issue) 2013: 314-324 Dezhen Yang et al the functions of resistance and temperature, and an The decomposition in axiomatic design electrical circuit as its stimulating and transmitting principles is an ideal process. In practice, there unit. figure 2 shows the first-level decomposition are several reasons why a system may be coupled, of FRs and DPs for TS. for example, implicit FRs and customer needs, The relationship between FRs and DPs for TS complexity of system components, system is mathematically expressed as constraints (Helander, et al., 2007). The AD principles did not give an approach to achieve the functional requirements sufficiently. Although the ((2) functional requirements are validated independent where FRR1 is sense the temperature; FRR2 through the independence axiom, it is still not a denotes stimulate and transmit the electrical signals good solution because of its insufficiency. As the of temperature; DP1 is thermistor; DP2 denotes previous example exhibits, the solution merely electrical circuit for stimulating and transmitting satisfies the fundamental requirements: measuring the signals. the temperature. It does not take stability and accuracy into account. Figure 1: Zigzagging to Decompose FRs and DPs Figure 2: Zigzagging Diagram for TS 316 AGJSR 31 )Special Issue) 2013: 314-324 Dezhen Yang et al Augmentation Process of Functional Do- between resistance and temperature should be main Considering Reliability Requirements eliminated. Therefore, two requirements have to be realized: In the axiomatic design principles, functional (a) Correcting the nonlinear errors between domain is a unified concept. To embody the resistance and temperature reliability requirements systematically, the (b) Preventing the changes of thermistor’s physical functional requirements should be subdivided into characteristics functions realization requirements and functions (2) Aiming at
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